US2684053A

US2684053A - High-speed internal-combustion reciprocating engine

Info

Publication number: US2684053A
Application number: US255881A
Authority: US
Inventors: Perdelli Ferdinando
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-05-11
Filing date: 1951-11-13
Publication date: 1954-07-20
Anticipated expiration: 1971-07-20

Description

July 20, 1954 F. PERDELLI 2,684,053

HIGH-SPEED INTERNAL-COMBUSTION RECIPROCATING ENGINE Filed Nov. 13, 1951 4 Sheets-Sheet l I N V EN TOR. E/vw/vmmo PERDEL L F. PERDELLI July 20, 1954 HIGH-SPEED INTERNAL-COMBUSTION RECIPROCATING ENGINE 4 Sheets-Sheet 2 Filed Nov. 13 1951 I INVENTOR. f'mw/wn/aa PA /P051 .4

F. PERDELLI 2,684,053

SPEED INTERNAL-COMBUSTION RECIPROCATING ENGINE July 20, 1954 HIGH- Filed Nov. 15 1951 4 Sheets-Sheet 3 am E I W -m 5 M M m w A J m m M E M 0 u firm M w. 5 5 m K P 0 I w 5 w o fl/EAN TORQUE INVENTOR. Fz/w/Am/voo Pawn A ATTO/PA/EX July 20, 1954 F. PERDELLI 2,684,053

SPEED INTERNAL COMBUSTION RECIPROCATING ENGINE HIGH- 4 Sheets-Sheet 4 Filed Nov. 15

INVEN TOR. Faw/m/voo 1 5/2054 1 ATTORNEY Patented July 20, 1954 UNITED spires serum orrlcr.

HIGH-SE'EED INTERNAL-COMBUSTION nEoirnocA'rING ENGINE Ferdinando ierdelli, Genoa, Italy Application November 13, 1951, Serial No. 255,881 Claims priority, application Italy May 11, 1948 Claims. 1

This application is a continuation-in-part of my copending applications, Serial No. 2,723 filed January 16, 1948 and Serial No.'92,318 filed May 10, 1949, both of which are now abandoned.

The present invention relates to reciprocating engines and is particularly applicable to internal combustion engines. The invention is applicable to two-cycle and Diesel engines as well as to fourcycle engines.

A reciprocating engine may be either a singleacting engine or a double-acting engine. In a single-acting engine, force is applied to the piston in one direction only. In a double-acting engine, force is applied to the piston alternately in opposite directions.

It is an object of the present invention to provide an improved engine having important advantages over both single-acting and doubleacting engines heretofore available.

With respect to single-acting engines using a conventional arrangement of connecting rods and a crank shaft for converting the reciprooatory movement of the pistons into rotary movement, the construction in accordance with the invention has the advantages of smaller size and less weight for a given horsepower and a higher efficiency with smaller fuel consumption. It is easy to assemble and disassemble, which is advantageous both in the manufacture and subsequent maintenance and servicing of the engine. The cost of construction and cost of upkeep are both low. The number and weight of movin parts of the engine are reduced with consequent re notion of friction and vibration. The construction in accordance with the invention also reduces radial components of thrust on the pistons, thereby reducing piston and cylinder wear and, in particular, the tendency of cylinders to become out-of-round.

With respect to conventional double-acting engines, the construction in accordance with the present invention has the additional advantages of eliminating the usual piston rod and stufiing box and the crosshead slide. It also provides combustion chambers of equal dimensions, reduces the size of the frame, operates at higher speeds with very little vibration and has greater responsiveness to control.

In particular, with the construction according to the present invention, it is possible to reduce the crank shaft radius, the length of the connecting rods, the weight of the reciprocating masses, th inertia stresses and friction and vibration in the engine.

The nature, objects and advantages of the invention will be more fully understood from the following description and accompanying drawings which show, by way of example, preferred embodiments of the invention.

In the drawings:

Fig. 1 is a longitudinal sectional view of an engine embodying the invention, being taken approximately on the line l-I of Fig. 2.

Fig. 2 is a cross-section taken approximately on the line 2-2 in Fig. 1.

Fig. 3 is a plan of the engine shown in Figs. 1 and 2.

Fig. 4 is a schematic diagram of the connections between the piston and the crank shaft.

Fig. 5 is a pressure-indicator diagram of the engine.

Fig 6 is a force diagram.

Figs. 7, 8 and 9 are fragmentary views corresponding to portions of Fig. 1 and showing modifications.

In Figs. 1, 2, 3, there is shown a two-cylinder four-cycle internal combustion engine embodying the invention. In each of the cylinders I, there is a piston 2 having a wrist pin 3 which is connected by a link 4 and a connecting pin 5 with the upper end of a rocking lever t which is swingable about a fixed fulcrum or axis i. These parts are the same for each of the cylinders, both or all of the levers 6 being preferably swingable about the same axis. Each of the levers t is provided with a pivot 8 which is connected by a connecting rod 9 with a crank ill on a crank shaft H, the main axis of which is parallel to the axis 1 about which the levers 6 swing. As illustrated in Fig. 1, the pivot t is laterally oifset from a line connecting the .f ul Clllll'l l and pin 5 of the lever 6, the pivot 8 and the crank shaft ll being disposed on opposite sides of this line. It will further be seen that each of the levers t is a second-class lever and that the lever arm from the fulcrum l to the pivotal connection 5 of the lever with the piston is greater than the lever arm from the fulcrum to the pivotal connection 3 of the lever with the con necting rod. 9. Preferably, the pivotal connection 8 is slightly more than half-way from the fulcrum l to the pivotal connection 5 at the upper end of the lever 5; At one end, the crank shaft ll carries a flywheel i2 while, at the other end, it carries a driving pulley it which, through a belt l4, operates pulley l5 of a fan l6 and a pulley on a shaft I? for driving an electric generator and a water pump. For a two-cylinder engine, shown inthe drawings, crank shaft has two cranks (Fig. 2') located The crank shaft is balanced for high speed operation.

However, because of the inherent self-balancing characteristics of the arrangement in accordance with the invention, no extensive counter-balancing is necessary.

At opposite ends of the cylinders i, there are provided explosion chambers 2i and guides 22 for the stems of valves 23. The axes of the valve stems are inclined towards the plane of symmetry of the engine (Fig. 1) so that the ends of the valve stems are nearer said plane than are the valve heads. The valves are operated by doublearmed levers 24 rocking about pivotal axes 25. The inner ends of the levers 24 are actuated by cams on a central cam shaft 26, all of the valves being operated by a single cam shaft. Removable caps 21 are provided in the walls of the combustion chambers opposite the valves to permit easy extraction of the valves. The cylinders are surrounded by a water jacket 28 for the circulation of cooling water. The thickness of the water jacket is reduced below the cylinders to permit the crank shaft and associated parts to be close to the cylinders, thereby providing a compact construction. The combustion chambers are provided with spark plugs 29 which are connected by leads 30 with a distributor 3|. The cam shaft 26 is driven from the crank shaft l l by operative connections including a driving chain 32 while the distributor 3| is likewise driven by an approximately vertical shaft driven from the crank shaft by suitable driving connections 33. The cam shaft 26 and rocker arms 24 are enclosed by a cover 35 which is provided with a V-shaped channel 36 serving as an intake manifold to con duct the fuel-air mixture from a centrally located carburetor 3! to the inlet valves 23. This arrangement contributes to the compactness of the engine and also assures uniformity of fuel distribution since the path of travel of the fuel-air mixture from the carburetor to each of the inlet valves is the same. A further advantage is that the fuel-air mixture passing through the V- shaped conduit 36 is pro-heated by oil contained in the chamber enclosing the valve-operation mechanism. Exhaust manifolds 36 are provided on opposite sides of the engine. The engine has a housing 40 comprising two housing sections 4! and 42 connected by bolts 43. The bearings for the crank shaft H and also the bearings for the shaft I forming the fulcrum of the rocking levers 6 are all contained in one of these housing portions, namely the portion 4|, so that the other portion 42 can be removed for inspection or servicing without in any way disturbing the crank shaft or the links and levers connecting the crank shaft with the pistons. The second housing portion 42 is provided with a space or chamber 45 for accommodating the generator and water pump which are arranged coaxially, with the generator in the forward portion of the space and the water pump in the rear portion, both being driven by shaft H. The housing portion 42 also accommodates a lubrication oil pump 45 which is driven by the same shaft that drives the distributor 3']. The ends of the cylinders are covered by removable heads 48 secured by bolts 49. These heads are quickly and easily removable for repairs, grinding valves, etc. without it being necessary to dismount or disturb the valve-operating gear. The engine housing is provided with opposite projections or trunnions 50 for mounting the engine and a connecting flange 5| for the change-speed gear or transmission.

The compactness and high efliciency of the engine in accordance with the invention is indicated by the fact that an engine measuring 19 inches by 12 inches by 13 inches develops 45 horsepower at 4500 R. P. M. The diameter of the cylinders is mm., the other dimensions of the engine bein deducible from Figs. 1 to 3 of the drawings which show, in correct proportion, an actual engine that has been successfully tested and operates.

The operating characteristics of an engine in accordance with the invention are illustrated in Figs. 4 to 6. The elements for transmitting iovement from the piston to the crank shaft are shown diagrammatically in Fig. 4. The lever 6 rocks about a fixed fulcrum A and is pivotally connected at B with the connecting link 4 which in turn is pivotally connected to the piston at C. At a point D intermediate its ends, the rocking lever 6 is pivotally connected to one end of the connecting rod 9, the other end of which rotatably engages a crank of the crank shaft H, the throw of the crank shaft being indicated by the line OE. In the particular embodiment illustrated by way of example, the dimensions of these parts are as follows:

Millimeters Length A-B of the rocking lever 6 250 Length of the portion AD 165 Length D--E of the connecting rod 9 108 Radius or throw OE of the crank shaft 2'? As the amplitude of oscillation of the rocking lever 6 is very small in comparison to its length, the paths of movement of the points D and B may be considered rectilinear. This hypothesis simplifies the study without substantially modifying the values of the stresses which act on the points D and B.

The several masses which have a reciprocating movement may be considered, for the purposes of calculation in a well known way, as masses which are concentrated at the point D and have equal pull or moment of inertia with respect to the axis of oscillation A. The piston, piston rings, connecting link 4 and the connecting eye at the upper end of the oscillating lever 6, which have a total weight of 0.950 kg. and act at a distance of 250 mm. from A, are equivalent to a weight of 0.950 (250/165) equals 2.180 kg. concentrated at D. The total weight of the oscillating lever B, excluding the pivot eyes A, B and C, is 0.240 kg. By a formula similar to the preceding one, it is determined that this is equivalent to a mass of 0.195 kg. concentrated at D. The total weight of the connecting rod is 0.735 kg. As the center of gravity of the connecting rod is at K, which is 25 mm. from the point E, the equivalent weight concentrated at the point D is 0.530 kg. The pivotal connections between the connecting rod and the oscillating lever 6 at point D is 0.210 kg. so that the total value of the connecting rod and connections is 0.740 kg. Thus, the sum of the equivalent weights of the several reciprocating or oscillating masses concentrated at the point D is:

The working cycle or indicator diagram of the engine is illustrated in Fig. 5 where the abscissae represent the stroke of the piston (82 mm.) and the ordinate represents cylinder pressure. As the engine is four-cycle and double-acting, the power corresponding to normal operation at 4500 R. P. M. is 22.5 horsepower for each cylinder if the organic efficiency is The mean acs noce indicated pressure is "-7."I5 kg./cm. and the effective pressure is 6.20 kg/cmi- The kinematic diagram may be considered as a connecting rod-crank systemm which:

Angle .of the crank with respec-t to upper dead point (positive in clockwise direction) (a) The mass stresses may now be calculated according to the well known formula:

The mass stresses have a negative efiect when the masses are accelerating and apositive effect when the masses are decelerating.

By the formula:

it is possible to calculate the intensity and direction of the tangential stress Ta acting on the .crank pivot owing to the mass stresses ll.

The diagram of Fig. 6 gives 'therresults of the calculations made in accordance with the above formula. In this figure, Tg represents the curve of the tangential stress due to the pressure of the gases in the cylinders (double-acting), Ta represents the tangential stress acting on the crank pivot owing to the reciprocating masses and T represents the algebraic sums of the values Taand To. lhe resulting stresses caused by the motionof the reciprocating masses are very low and have, in fact, been found to be only approximately 50% as high as those in a conventional double-acting reciprocat'ingengine. These low stresses permit efiicient high speed operation of the engine and also make possible a considerable saving in weight.

While a particular motor has been described in detail as an example, it will be understood that the invention is not limited to a particular size of engine. .t may be made smaller or maybe much larger. It is particularly suitable, for example, for automotive vehicles, including tractors, aircraft, including helicopters, locomotives, motor ships and submarines.

A modified arrangement of the connections between the pistons and the crank shaft is illustrated in Fig. 7 in which like parts are designated by the same reference numerals as in Figs. 1 to 3. In this embodiment, each double-ended piston 2 is recessed or slotted at its middle as indicated at 2a to receive the upper end of the rocking lever B which is pivotally connected to the piston by a central wrist pin 60. The oscillating levers 6 swing about a movable fulcrum provided by a shaft fil carried by spaced arms 62 pivotally supported on the housing 49 with a pivotal axis 63 that is parallel to the crank shaft.

Figs. 8 and 9 show other ways of connecting the oscillating lever B to the piston 2. In the embodiment of Fig. 8, the lever 6 is provided with a bulbous upper end having surfaces which are either spherical or cylindrical with an axis parallel to the pivotal axis of the lever 8. The bulbousupper end 70 of the lever 5 is received in the central portion of the double-ended cylinder 2 and is slidable in a sleeve or hearing ii provided in the central portion of the piston. In the embodiment shown in Fig. 9, the bulbous upper end 70 of the oscillating lever 6 is received in a bushing 12 having internal curved surfaces corresponding to the external surfaces of the bulbous end 10 so as to provide, in effect, a ball and socket connection. The bushing i2 is in turn slidable transversely of the piston in a bearing 13 provided in the central portion of the piston. 'In the embodiments of Figs. 8 and 9, the lever 5 swings about a fixed fulcrum as in Figs. 1 to 3 "rather than "about a movable fulcrum as in Fig. '7.

It will be understood by those skilled in the art that still further modifications are possible within the scope of the appended claims and it is accordinglynot intended to limit the invention to the specific embodiments that have been shown in the drawings and particularly described by way of example.

What I claim and desire to secure by Letters Patent is:

1. In a high speed internal combustion engine, an engine block comprising a plurality of parallel cylinders and a crank case, said crank case comprising two sections, each of said cylinders having an opening in the side thereof opening into the interior of the crank case, a doubleended, double acting piston reciprocable in each cylinder, a second class lever pivotally connected at one end to the piston and projecting laterally therefrom at a point intermediate the ends of the piston, said lever extending through the opening in the cylinder wall into the interior of the crank case, a pivotal connection between the opposite end of each lever and one section of the crank case, providing a fulcrum for each lever, a crank shaft rotatably supported by the same section of the crank case that provides the f-ulcrums for said levers, the axis of the crank shaft being parallel to that of said fulcrurns and being disposed at one side of said levers, said crank shaft having a crank for connection to each lever, and a link pivotally connected at one end to each lever intermediate its ends and r0- tatably connected at the other end to a corresponding crank of the crank shaft, the section of the crank case other than that supporting the crank shaft being removable to provide access to the interior of the crank case without disturbing the crank shaft or the fulcrums of said lovers.

2. In a high speed internal combustion engine, an engine block comprising a double-ended cylinder, and a crank case, said crank ease comprising two sections, said cylinder having an opening in the side thereof opening into the interior of the crank case, a double-ended, double-acting piston reciprocable in said cylinder, a second class lever pivotally connected at one end to the piston and projecting laterally therefrom at a point intermediate the ends of the piston, said lever extendin through the opening in the cylinder wall into the interior of the crank case, a pivota1 connection between the opposite end of said lever and one section of the crank case, providing a fulcrum for said lever, a crank shaft rotatably supported by the same section of the crank case that provides the fulcrum for said lever, the axis of said crank shaft being parallel to that of said fulcrum and being disposed at one side of said lever, said crank shaft having a crank for connection to said lever, and a link pivotally connected at one end to said lever intermediate its ends and rotatably connected at the other end to said crank of the crank shaft, a section of the crank case other than that supporting the crank shaft being removable to provide access to the interior of the crank case without disturbing the crank shaft or the fulcrum of said lever.

3. In a high speed internal combustion engine, an engine block comprising a double-ended cylinder, and a crank case, said crank case comprising two sections, said cylinder having an opening in the side thereof opening into the interior of the crank case, a double-ended, double-acting piston reciprocable in said cylinder, a second class lever pivotally connected at one end to the piston and projecting laterally therefrom at a point intermediate the ends of the piston, said lever extending through the opening in the side of the cylinder into the interior of the crank case, a pivotal connection between the opposite end of said lever and one section of the crank case, providing a fulcrum for said lever, a crank shaft rotatably supported by the same section of the crank case that provides the fulcrum for said lever, the axis of said crank shaft being parallel to that of said fulcrum and being disposed at one side of said lever, said crank shaft having a crank for connection to said lever, a bearing carried by said lever intermediate its ends, said bearing being oifset laterally from a line connecting the ends of said lever in a direction away from said crank shaft,

and a link pivotally connected at one end to said lever by means of said bearing and rotatably connected at the other end to said crank, a section of the crank case other than that supporting the crank shaft being removable to provide access to the interior of the crank case without disturbing the crank shaft or the fulcrum of said lever.

4. In an internal combustion engine, an engine block comprising a double-ended cylinder, and a crank case comprising two sections, said cylinder having an opening in its lower side opening into the interior of the crank case, a double-ended, double-acting piston reciprocable in said cylinder, 9, second class lever pivotally connected at one end to said piston midway between its ends and extending through said opening into the crank case, a pivotal connection between the opposite end of said lever and one section of the crank case, providing a fulcrum for said lever, a crank shaft having a crank and rotatably supported by the same section of the crank case that provides the fulcrum for said lever, the axis for said crank shaft being parallel to that of said fulcrum and being disposed below said cylinder and at one side of said lever, a connecting rod having at one end a bearing rotatably engaging said crank and pivotally connected at the opposite end to said lever intermediate its ends, a section of the crank case other than that supporting the crank shaft and said fulcrum being removable to provide access to the interior of the crank case without disturbing said crank shaft or fulcrum.

5. In an internal combustion engine, an engine block comprising axially aligned opposed cylinders, and a crank case comprising a plurality of sections, said cylinders opening into the interior of said crank case, opposed pistons reciprocable in said cylinders, means connecting said pistons together, a second class lever pivotally connected at one end to said means connecting said pistons approximately midway between the opposite ends of said pistons, a pivotal connection between the opposite end of said lever and one section of the crank case, providing a fulcrum for said lever, said fulcrum and the opposite ends of said cylinders defining an approximately equilateral triangle, a crank shaft having a crank and rotatably supported by the crank case with its axis parallel to that of said fulcrum and disposed approximately at the midpoint of a side of said equilateral triangle joining said fulcrum with an end of one of said cylinders, said lever having intermediate its ends a laterally offset portion projecting away from said crank shaft, a connecting rod having at one end a bearing r0- tatably engaging said crank and pivotally connected at the opposite end to said offset portion of said lever, a section of the crank shaft other than the portion supporting said fulcrum and crank shaft being removable to provide access to the interior of the crank case without disturbing said crank shaft or fulcrum.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 42,527 Campbell et al Apr. 26, 1864 334,039 Nash Jan. 12, 1886 578,112 Nash Mar. 2, 1897 1,378,875 Knox May 24, 1921 1,505,976 Spohrer Aug, 26, 1924 1,616,137 Palmer Feb. 1, 1927 1,719,537 Dulche July 2, 1929 FQREIGN PATENTS Number Country Date 26,514 Great Britain Nov. 30, 1907 394,342 Great Britain June 19, 1933